1. Field of the Invention
The present invention relates to a ring light guide device for a camera, and more particularly, the present invention relates to a ring light guide device for a camera, which can align a position of a light source and a photographing direction of a lens of the camera on the same straight line and adjust an amount of light emitted from the light source depending upon a camera-to-object distance, thereby preventing a shaded region from being formed on an object upon photographing, and which can filter light irregularly reflected in the course of photographing any particular part of the body of a hospital patient especially when such body part includes a liquid constituent, thereby preventing the affected body part from being imaged more brightly than other parts, that is, to have a white color.
2. Description of the Related Art
Generally, when it is necessary to enlargedly image a small object such as an insect, flower or the like, contact or close-up photography is implemented. Also, in order to precisely inspect mechanical or electronic components for a defect in the course of the manufacture thereof along an assembling line, the components are imaged by contact photography using a high performance camera, and then, based on developed photographs, a defect and a location thereof are determined.
Further, when it is difficult to directly see an ill-affected body part of a medical patient with the naked eye, due to an internal injury rather than an external injury, that is, as in medically treating a patient in a dental clinic, the inside of the oral cavity of the patient is precisely photographed, and a status of the affected part is grasped based on photographs which are obtained by this photography. Moreover, in the case of medically examining a patient in obstetrics and gynecology, a cervical region of the uterus of the patient, for example, is photographed with a camera, and based on obtained photographs, whether a uterine disease is developed and if developed, a degree of the development may be determined.
However, in the conventional art, as can be clearly seen from FIG. 1, in the case that a mechanical component 10 which is formed with a prominence and depression or a recessed portion, is photographed, because a flash 5 of a camera 1 is located at a predetermined separation from a lens 3, that is, the flash 5 of the camera 1 is not arranged on a photographing direction of the lens 3, a shaded region S results in the prominence and depression or the recessed portion of the mechanical component 10. Therefore, since the shaded region S is more darkly imaged than other regions on the resultant photograph, it is difficult to precisely know a status of the component 10.
On the other hand, when a patient is photographed in a hospital, in most cases, the ill body part of the patient includes a liquid constituent such as saliva which irregularly reflects light. If such a body part is photographed in a state wherein the liquid constituent is not removed and a resultant film is developed, on the affected part including the liquid constituent, light which is emitted from a light source, is irregularly reflected by the liquid constituent toward a lens. Consequently, because, on the photograph obtained, the affected part is more brightly imaged than other parts, to be white, it is difficult to precisely read out a current status of the affected part.
While an attempt has been made in which a separate large-sized light source is provided integrally with a camera to cope with this problem, in this case, troublesomeness is induced in that a size of a main camera body is remarkably enlarged and it may be necessary to laboriously manipulate the separate large-sized light source.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a ring light guide device for a camera, which effectively prevents, by using a flash mounted to the camera and without using a separate light source, a shaded region from being formed on an object upon photographing and enables a photographing operation to be performed at an illumination intensity suited to a camera-to-object distance.
Another object of the present invention is to provide a ring light guide device for a camera, which renders a polarization function to the camera and thereby prevents, when, for example, an affected body part of a medical patient includes a liquid constituent, the affected part from being imaged more brightly than other parts, that is, to have a white color, by filtering irregularly reflected light through polarized filters.
Still another object of the present invention is to provide an adaptor for a camera, which can adjust an amount of light irradiated to an object depending upon a camera-to-object distance and render a polarization function to the camera.
Yet still another object of the present invention is to provide a ring light guide device for a camera, in which a light receiving section coupled to a light source of the camera and a lens coupling section coupled to a lens of the camera are configured in a manner such that they are integrated with or separated from each other.
In order to achieve the above objects, according to one aspect of the present invention, there is provided a ring light guide device for a camera, comprising: a housing having an adaptor inserting hole which is formed therethrough at a side thereof in a manner such that the adaptor inserting hole has an axis which is coaxial with a center axis of a lens of the camera, the housing being detachably coupled on a rear surface thereof with a camera fitting adaptor by the fact that the camera fitting adaptor is inserted into the adaptor inserting hole, light receiving means installed opposite to a light source of the camera, for receiving light which is emitted from the light source; light path changing means for changing a path of light received by the light receiving means in a manner such that the light is irradiated toward an object in a direction which is substantially parallel to the center axis of the lens of the camera; and irradiation adjusting means for adjusting an amount of light which is irradiated to the object, depending upon a camera-to-object distance.
According to another aspect of the present invention, there is provided a ring light guide device for a camera, comprising: light receiving means arranged in front of a light source of the camera for receiving light which is emitted from the light source; light path changing means for changing a path of light received by the light receiving means in a manner such that the light is irradiated toward an object in a direction which is substantially parallel to a center axis of a lens of the camera; and irradiation adjusting means for adjusting an amount of light which is irradiated to the object, depending upon a camera-to-object distance.
The irradiation adjusting means can comprise first and second polarized filters located over an entire light receiving area of the light receiving means for adjusting, depending upon an angle which is defined between their polarization axes, an amount of light to be received by the light receiving means, or first and second polarized filters located at an output side of the light path changing means for adjusting, depending upon an angle which is defined between their polarization axes, an amount of light to be received by the light receiving means, the first and second polarized filters having a ring-shaped configuration.
The irradiation adjusting means can further comprise a third polarized filter located in front of the lens of the camera for receiving only reflected light which is reflected from the object after being irradiated through the first and second polarized filters to the object. In this case, by the fact that the first and second polarized filters are simultaneously rotated along with and relative to the third polarized filter in a state wherein their polarization axes are aligned on the same straight line, it is possible to render a polarization function to the camera.
Moreover, the irradiation adjusting means can comprise a first polarized filter located at an output side of the light path changing means for allowing only one linear polarized light component of light to be irradiated, the first polarized filter having a ring-shaped configuration; and a second polarized filter located in front of the lens of the camera for receiving only reflected light which is reflected from the object after being irradiated through the first polarized filter to the object.
According to another aspect of the present invention, the irradiation adjusting means can comprise a movable member located in front of the light source of the camera in a manner such that the movable member can be moved in forward and rearward directions, the movable member having light receiving means arranged therein; and distance altering means threadedly coupled around a circumferential outer surface of the movable member, for altering a distance between the light source of the camera and the light receiving means.
Further, the irradiation adjusting means can be constructed in a manner such that it automatically adjusts a light irradiation amount depending upon the camera-to-object distance and a brightness of the object, by using an automatic flash control circuit which is arranged inside the camera.
On the other hand, in the case that the ring light guide device further comprises a magnification lens located forward of the lens of the camera for enlarging an incident image to a preset magnification, it is possible to increase a magnification upon implementing a close-up photographing operation.
In this case, the light receiving means and the irradiation adjusting means can be coupled to the camera in a state wherein they are separated from or integrated with each other. In the case of a separation type, the light path changing means can be covered by a flexible bellows tube, whereby optical fibers provided therein are protected and a contour of the optical fibers can be freely varied.
By the features of the present invention, since light is emitted through light path changing means from a multitude of points in directions which are parallel to a photographing direction of a lens, it is possible to prevent a shaded region from being formed on a portion of an object, that is, in a prominence and depression or a recessed portion of a mechanical component. Therefore, the mechanical component can be photographed in a state wherein it does not have any shaded regions, and thereby, a status of the mechanical component can be precisely grasped.
Also, in the case that an ill-affected part of a medical patient, which includes a liquid constituent, is photographed, by filtering irregularly reflected light through polarized filters of a light amount/polarization adjusting section, it is possible to prevent from the affected part from being more brightly imaged than other parts.